#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
custom_serial_upgrade.py
基于串口的自定义固件升级协议
- 协议格式：2字节命令 + 2字节总长度 + N字节数据区 + 4字节保留 + 2字节CRC16校验
"""

import serial
import struct
import os
import time
from typing import Optional, Tuple


# 自定义CRC16校验（覆盖命令+总长度+数据区+保留）
def custom_crc16(data: bytes) -> int:
    crc = 0xFFFF
    for byte in data:
        crc ^= byte
        for _ in range(8):
            if crc & 0x0001:
                crc >>= 1
                crc ^= 0xA001  # 多项式（与Modbus一致，确保兼容性）
            else:
                crc >>= 1
    return crc & 0xFFFF


# XMODEM CRC16（块级数据校验）
def xmodem_crc16(data: bytes) -> int:
    crc = 0
    for b in data:
        crc ^= (b << 8)
        for _ in range(8):
            if crc & 0x8000:
                crc = (crc << 1) ^ 0x1021
            else:
                crc <<= 1
            crc &= 0xFFFF
    return crc


# CRC32（全局文件校验）
crc32_table = [
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcaebe28a, 0x53b3a330, 0x24b493a6, 0xbad02615, 0xcdd71683, 0x54de4739, 0x23d977af,
    0xb3666a2e, 0xc4615ab8, 0x5d680b02, 0x2a6f3b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
]


def crc32_incremental(data: bytes, prev_crc: int = 0) -> int:
    crc = prev_crc ^ 0xFFFFFFFF
    for byte in data:
        crc = (crc >> 8) ^ crc32_table[(crc ^ byte) & 0xFF]
    return crc ^ 0xFFFFFFFF


class CustomSerialUpgrader:
    def __init__(self,
                 port: str = "/dev/ttyUSB0",
                 baudrate: int = 115200,
                 block_size: int = 256,
                 max_retry: int = 10,
                 timeout: float = 2.0):
        self.serial = serial.Serial()
        self.serial.port = port
        self.serial.baudrate = baudrate
        self.serial.bytesize = serial.EIGHTBITS
        self.serial.parity = serial.PARITY_NONE
        self.serial.stopbits = serial.STOPBITS_ONE
        self.serial.timeout = timeout
        self.serial.write_timeout = timeout

        self.block_size = block_size
        self.max_retry = max_retry
        self.timeout = timeout

        # 固件信息
        self.firmware_path = None
        self.file_size = 0
        self.total_blocks = 0
        self.global_crc32 = 0

    def open(self) -> bool:
        """打开串口"""
        if not self.serial.is_open:
            try:
                self.serial.open()
                print(f"[INFO] 串口已打开: {self.serial.port} @ {self.serial.baudrate}")
                return True
            except Exception as e:
                print(f"[ERROR] 串口打开失败: {e}")
                return False
        return True

    def close(self):
        """关闭串口"""
        if self.serial.is_open:
            self.serial.close()
            print("[INFO] 串口已关闭")

    def set_firmware(self, firmware_path: str):
        """设置固件文件并预处理（计算大小、块数、全局CRC32）"""
        if not os.path.exists(firmware_path):
            raise FileNotFoundError(f"固件文件不存在: {firmware_path}")
        self.firmware_path = firmware_path
        self.file_size = os.path.getsize(firmware_path)
        self.total_blocks = (self.file_size + self.block_size - 1) // self.block_size

        # 计算全局CRC32
        crc = 0
        with open(firmware_path, 'rb') as f:
            while True:
                data = f.read(4096)
                if not data:
                    break
                crc = crc32_incremental(data, crc)
        self.global_crc32 = crc & 0xFFFFFFFF
        print(f"[INFO] 固件信息: 大小={self.file_size}B, 块数={self.total_blocks}, 全局CRC32=0x{self.global_crc32:08X}")

    def _pack_frame(self, cmd: int, data: bytes) -> bytes:
        """打包自定义协议帧：2字节命令 + 2字节总长度 + 数据区 + 4字节保留 + 2字节CRC16"""
        total_len = len(data)
        frame_body = struct.pack('<HH', cmd, total_len) + data + b'\x00\x00\x00\x00'  # 保留4字节暂填0
        crc = custom_crc16(frame_body)
        frame = frame_body + struct.pack('<H', crc)
        return frame

    def _unpack_frame(self, frame: bytes) -> Tuple[Optional[int], Optional[bytes]]:
        """解析自定义协议帧，返回命令和数据区（校验失败返回None）"""
        if len(frame) < 2 + 2 + 4 + 2:  # 最小帧长度：命令(2)+总长度(2)+保留(4)+CRC(2)
            return None, None
        # 校验CRC
        crc_received = struct.unpack('<H', frame[-2:])[0]
        frame_body = frame[:-2]
        crc_calc = custom_crc16(frame_body)
        if crc_received != crc_calc:
            print(f"[WARN] CRC校验失败: 接收0x{crc_received:04X}, 计算0x{crc_calc:04X}")
            return None, None
        # 解析命令和总长度
        cmd, total_len = struct.unpack('<HH', frame_body[:4])
        data = frame_body[4:-4]  # 数据区 = 帧体[4:-4]（排除保留4字节）
        # 验证总长度是否匹配
        if len(data) != total_len:
            print(f"[WARN] 总长度不匹配: 声明{total_len}B, 实际{len(data)}B")
            return None, None
        return cmd, data

    def _send_and_wait_ack(self, cmd: int, data: bytes) -> Tuple[bool, bytes]:
        """发送帧并等待ACK响应（命令码需一致）"""
        frame = self._pack_frame(cmd, data)
        retry = 0
        while retry < self.max_retry:
            try:
                self.serial.flushInput()  # 清空接收缓存
                self.serial.write(frame)
                print(f"[SEND] 命令=0x{cmd:04X}, 数据长度={len(data)}B")

                resp = self.serial.read(1024)  # 最大读取1024字节（可根据实际调整）
                print(resp)
                if not resp:
                    retry += 1
                    print(f"[WARN] 未收到响应，重试({retry}/{self.max_retry})")
                    time.sleep(0.1)
                    continue

                resp_cmd, resp_data = self._unpack_frame(resp)
                if resp_cmd is None:
                    retry += 1
                    print(f"[WARN] 响应解析失败，重试({retry}/{self.max_retry})")
                    continue

                if resp_cmd == cmd:
                    return True, resp_data
                else:
                    retry += 1
                    print(f"[WARN] 命令码不匹配: 发送0x{cmd:04X}, 接收0x{resp_cmd:04X}, 重试({retry}/{self.max_retry})")
            except Exception as e:
                retry += 1
                print(f"[ERROR] 发送/接收失败: {e}, 重试({retry}/{self.max_retry})")
                time.sleep(0.1)
        return False, b''

    def upgrade(self) -> bool:
        """执行固件升级全流程：握手→文件头→数据块→最终校验"""
        if not self.firmware_path or not self.serial.is_open:
            print("[ERROR] 请先设置固件文件并打开串口")
            return False

        # 1. 握手阶段（命令0x0001，数据区b'\x01'表示请求升级）
        print("\n[步骤1/4] 发送升级请求...")
        success, resp_data = self._send_and_wait_ack(0x0001, b'\x01')
        if not success or resp_data != b'\x00':  # 从机返回0x00表示就绪
            print("[ERROR] 从机未就绪或拒绝升级")
            return False
        print("[OK] 从机已就绪，准备接收固件")

        # 2. 文件头阶段（命令0x0002，数据区包含固件元信息）
        print("\n[步骤2/4] 发送文件头...")
        header_data = struct.pack('<I I H I',
                                  self.file_size,
                                  self.total_blocks,
                                  self.block_size,
                                  self.global_crc32)
        success, resp_data = self._send_and_wait_ack(0x0002, header_data)
        if not success or resp_data != b'\x00':  # 0x00表示文件头接收成功
            print("[ERROR] 文件头发送失败")
            return False
        print("[OK] 文件头接收成功，开始传输数据块")

        # 3. 数据块传输阶段（命令0x0003，每块包含索引、数据、CRC16）
        print("\n[步骤3/4] 传输数据块...")
        with open(self.firmware_path, 'rb') as f:
            for block_idx in range(self.total_blocks):
                f.seek(block_idx * self.block_size)
                block_data = f.read(self.block_size)
                block_len = len(block_data)
                block_crc16 = xmodem_crc16(block_data)

                # 数据区：块索引(4B) + 块长度(2B) + 块数据 + 块CRC16(2B)
                data = struct.pack('<I H', block_idx, block_len) + block_data + struct.pack('<H', block_crc16)
                success, resp_data = self._send_and_wait_ack(0x0003, data)

                if not success or (resp_data and resp_data[0] != 0x00):
                    print(f"[ERROR] 块{block_idx}传输失败")
                    return False
                print(f"[OK] 块{block_idx}/{self.total_blocks} (长度={block_len}B) 传输完成")

        # 4. 最终校验阶段（命令0x0004，请求从机全局校验）
        print("\n[步骤4/4] 等待从机校验...")
        success, resp_data = self._send_and_wait_ack(0x0004, b'\x01')
        if not success:
            print("[ERROR] 未收到校验结果")
            return False

        if resp_data == b'\x00':
            print("[SUCCESS] 固件升级成功，从机校验通过！")
            return True
        else:
            print(f"[ERROR] 从机校验失败，响应码: {resp_data.hex()}")
            return False


if __name__ == "__main__":
    # 配置参数（根据实际设备修改）
    SERIAL_PORT = "COM16"  # Windows填"COMx"，Linux填"/dev/ttyUSBx"
    BAUDRATE = 115200
    FIRMWARE_PATH = "app.bin"  # 替换为实际固件路径

    upgrader = CustomSerialUpgrader(
        port=SERIAL_PORT,
        baudrate=BAUDRATE,
        block_size=4096,
        max_retry=30,
        timeout=2.0
    )

    try:
        if upgrader.open():
            upgrader.set_firmware(FIRMWARE_PATH)
            # confirm = input("确认开始升级？(y/n): ").strip().lower()
            # if confirm == 'y':
            upgrader.upgrade()
    finally:
        upgrader.close()
